Proton Mail Alternatives for Business Teams

Proton Mail works well for one person who wants zero-access encryption. It is a harder product for a team that needs a shared support@ inbox, a delegated assistant on the founder's mail, and an admin console that can revoke a departing employee's access without breaking everything else. Proton for Business ships the mailbox and Proton Calendar, but shared mailboxes with per-agent replies and true delegation are not part of the model — a zero-access mailbox is by definition one no one else can read.

This page is for the reader who has decided they want a private email provider that behaves like a team platform. It ranks the business-capable alternatives, is explicit about which team features you give up with end-to-end encrypted storage, and includes Google Workspace and Microsoft 365 honestly — pretending those two are not the reference standard for team mail would waste the reader's time.

The short answer#

If your team needs shared mailboxes, delegated inbox access, and an admin console that survives an employee leaving, the top pick among the private-leaning providers is Fastmail Teams. Native IMAP means any client works, delegation is first-class, admin controls are simple and readable, and the team plan bills per-mailbox with no seat minimum. It is not encrypted-at-rest the way Proton advertises — that is the trade the rest of this page keeps returning to.

For teams that will not budge on encrypted-at-rest storage, Mailbox.org is the closest workable answer — a German provider with team packages, admin controls, and an integrated OpenPGP layer that can encrypt inbound mail on arrival with keys you hold. You do not get zero-access; you do get a genuinely private, team-shaped mailbox that will file a legal request differently to Fastmail or Zoho.

The honest concession: if your company has standardised on Google Workspace or Microsoft 365 for identity, calendars, drive and video, those two outclass every option on this page for shared-inbox depth and admin controls. Neither is private in Proton's sense, and neither pretends to be. Switching mail providers alone while keeping Workspace or Microsoft 365 underneath for everything else is almost certainly moving cost around rather than solving anything.

We build AI Emaily — a mail client, not a mail provider — so we do not rank ourselves at the top of a provider roundup. AI Emaily sits on top of whichever provider you pick and adds the AI layer: triage, drafts in a voice you set through a Personal Context brain, and Copilot approval before anything sends. That section is at the end, disclosed as ours.

How we compared#

The criteria that decide a business-mail move are narrower than the general-purpose privacy shortlist. Every provider was checked against current vendor documentation for four things: whether it ships real shared mailboxes with per-agent identity on replies; whether it supports delegation without password sharing; how deep the admin console goes for role assignment, offboarding and audit; and what encryption is offered, at what layer, with what practical consequences for team search and mobile access.

We describe packaging shape — free trial, per-seat, seat minimums, annual discount — and point to the vendor's live pricing page for numbers. Team mail pricing has moved several times in the past year; a figure printed here would be stale. Verify current plans on the vendor's own page before you migrate.

Business-capable Proton Mail alternatives at a glance#

Read the shared-mailbox and delegation columns first — that is where Proton Business falls short and where the ranking is decided. The last column names the trade each option is asking you to accept.

Where the trade actually lives#

No one row wins outright because encryption-at-rest and shared-inbox delegation push in opposite directions. A shared mailbox is one multiple people can read; a delegated inbox is one a second person can read. Both require the server to decrypt and re-serve the message to whoever is entitled to see it — the exact opposite of a zero-access design where the server holds ciphertext it cannot read.

The grid below shows that trade at a glance before you commit to a migration. It is not scoring — it is where each provider sits on the axis every reader here is choosing on.

Fastmail Teams#

Fastmail is the default answer among the private-leaning providers when the requirement is a working team mailbox with delegation and clean admin. The company has been independent for more than two decades, its team co-authored the JMAP standard now used by clients like Apple Mail on iOS 26, and the team plan is built around the shared-inbox and delegation workflows a small business actually needs.

Shared mailboxes are first-class: a support@ or sales@ address behaves like a real mailbox where any authorised agent can reply from the shared identity or their own. Delegation of one user's inbox to another is a checkbox rather than a workaround. Admin controls cover per-user roles, custom domains, aliases, quota, and log export, and there is no seat minimum on the team plan.

The trade Fastmail is upfront about: message bodies are stored on its servers in a form Fastmail can read — that is what makes shared mailboxes and delegation work, and it is the opposite of Proton's zero-access design. Fastmail also sits under Australian jurisdiction, which matters for some threat models; read their transparency reports and current stance on the Assistance and Access Act before assuming European-style protection.

Mailbox.org#

Mailbox.org is the Berlin-based provider to look at first if your team was on Proton for the threat model rather than the branding. Team packages include per-user admin, custom domains, shared calendars and contacts through CalDAV and CardDAV, and shared folders that give a small team a workable common surface without becoming Google Groups.

Where Mailbox.org gets closer to Proton's story is the OpenPGP integration. Inbound mail can be encrypted on arrival with keys you hold, and a paid guard-mailbox add-on tightens the on-server story further. None of that is transparent the way Proton is — you set it up, and it interacts with IMAP in the usual PGP ways: encrypted bodies stay encrypted to your client, search over encrypted content is limited, and mobile key management is your problem.

Jurisdiction is Germany, with a public transparency record on lawful-access requests. Packaging is a modest per-mailbox monthly fee with a 30-day trial; team plans layer admin and shared resources on top. Check the current tier layout on the vendor page before you migrate — the tier names have moved once in the past year.

Zoho Mail#

Zoho Mail earns its place for a specific reader: the small business that wants a working team mailbox on a custom domain, with real shared inboxes and a deep admin console, at the lowest sustainable price on the page. Native IMAP is available on paid plans, and the Zoho Workplace bundle includes the rest of the Zoho office suite if you want it.

The team-mail features are genuinely deep: shared inboxes support agent assignment, internal notes and status tracking closer to a lightweight help-desk than a plain shared folder. Delegated access is straightforward. The admin console covers org units, roles, retention, group policies, and an e-discovery add-on for teams that need it. Data residency can be pinned to the EU on request, addressing the standard objection for European teams.

The privacy story is thinner than the European providers above — Zoho is ad-free but not zero-access, and it does not attempt Proton's threat model. It is genuinely private in the ordinary sense: no ads scanning mail contents, no data sold, the business funded through the wider Zoho product line rather than your inbox. For a team that wants deep team-mail features on a private-ish base at the lowest price, this is the honest first look.

Google Workspace#

Google Workspace is on this page because it is the reference standard for team mail and pretending otherwise would waste the reader's time. Shared mailboxes run through Google Groups Collaborative Inbox — one address, many members, per-agent replies, status tracking. Delegation of one Gmail inbox to another is a native feature any admin can enable. The Admin console covers identity, roles, DLP, Context-Aware Access, and Vault for retention and eDiscovery.

The reason a reader leaves Google Workspace for Proton is almost never the mail workflow — it is the privacy posture, the ad ecosystem, and the fact that message content is legible to Google. Returning for a team means accepting that trade. Google offers Client-Side Encryption on select surfaces for enterprise plans, bringing some of the zero-access story to specific data — but general mail search, mobile access and third-party integrations run on server-readable content.

Packaging is per-user monthly with Business Starter, Standard, Plus and Enterprise tiers, an annual discount, and a free trial. For teams already standardised on Workspace for identity, calendar, drive and video, staying on Workspace mail and layering a privacy-respecting client (see the AI Emaily section below) is a saner move than switching mail providers alone.

Microsoft 365#

Microsoft 365 is the other reference standard. Exchange shared mailboxes are the canonical implementation — a real mailbox with no license consumed for the shared identity, supporting Send As, Send On Behalf, and Full Access permissions with per-user granularity. Delegation is the model Exchange has shipped for two decades. The admin surface — Microsoft 365 admin center, Exchange admin center, Purview and Defender — is the deepest on this page and the same surface most enterprise IT teams already know.

The reason a reader would leave Microsoft 365 for Proton has the same shape as the Google case: the privacy posture, the ad-adjacent identity graph, and legible message content. Microsoft offers Double Key Encryption for select scenarios, but the general mail workflow runs on server-readable content.

Packaging is per-user monthly with Business Basic, Standard and Premium tiers plus Enterprise plans; the licensing model is the deepest to navigate here. For teams already on Microsoft 365 for Office, Teams, SharePoint and identity, staying on Exchange for mail and adding a privacy-disciplined client is again the saner move than switching mail providers alone.

Kolab Now#

Kolab Now is a Swiss-hosted groupware suite built on the Kolab open-source stack — mail, calendar, contacts, files, chat and video, delivered as a single hosted bundle. Native IMAP works with any client, and it is one of the few providers on this list that also speaks JMAP via the Cyrus implementation. Shared folders and identities make shared mailboxes a real feature rather than a convention.

The reason to pick Kolab is not the mail alone — Fastmail is smoother, Mailbox.org is cheaper. The reason is if the team wants a Proton-alternative-plus-everything-else: a Swiss-hosted, open-source groupware suite that replaces the workspace stack the team might otherwise stitch together, with IMAP so any trusted client still connects, and per-user roles across mail, calendar, files and chat in one admin surface.

Jurisdiction is Switzerland, with its own legal considerations distinct from EU jurisdictions. Encryption is standard TLS-in-transit and at-rest server storage — no zero-access. Packaging is per-user monthly with a Group Manager plan for teams; check current tiers before you commit, as naming has evolved with the underlying Kolab releases.

Mailfence#

Mailfence is a Belgian provider serving the privacy-leaning small-business market since 2013. Business plans include custom domains, group accounts with shared calendar and contacts, group administration, and Belgian jurisdiction under EU privacy law — outside the concerns some readers raise about US and Australian providers.

The distinctive piece is built-in OpenPGP: key generation, storage and signing happen inside the Mailfence web client without a separate PGP plugin — which is why teams that want encrypted mail between members without requiring Thunderbird with Enigmail end up here. Two-factor authentication, a document store and an integrated calendar round out the bundle.

The honest limits: shared inboxes with per-agent identity are thinner than Fastmail or Zoho, and delegation is not the first-class feature it is on the top three rows. For a small team that wants a European, privacy-first mailbox with built-in PGP and shared calendar and contacts, Mailfence fits. For a team whose day is driven by a shared support@ inbox with agent assignment and status tracking, look at Fastmail or Zoho first.

AI Emaily — the client layer, disclosed#

The order matters: pick the provider first, then pick the client. AI Emaily is the client. We are not a mail provider, we do not host mailboxes, and ranking ourselves at the top of a provider roundup would be dishonest. The reader on this page needs a business-capable mailbox first; the honest top pick for that among the private-leaning options is Fastmail Teams. We build AI Emaily, and this section is the disclosure.

Where AI Emaily fits is once the mailbox is chosen. You point AI Emaily at any of the providers above — Fastmail, Mailbox.org, Zoho, Google Workspace, Microsoft 365, Kolab Now or Mailfence — over IMAP, Gmail API or Microsoft Graph, and get an AI-native inbox on top: triage that routes shared-inbox mail to the right agent, drafts written in a voice you set through a Personal Context brain and per-client profiles, Copilot mode that always requires human approval before sending, and Autopilot for the specific routine actions you explicitly allow. Every action is undoable and audited.

The reason a team reading a privacy-first page would still bring in a third-party client is that the privacy discipline extends through to the client: OAuth tokens and message bodies are encrypted at rest, model providers see no content that is used for training, and BYOK is available if your team wants to run against its own model key rather than ours. Packaging is a 7-day free trial on the Pro plan (card required, $0 if cancelled before day 7) — there is no permanent free tier. Team pricing is separate and does not run through the individual trial. See /pricing for current numbers and /security for the privacy model in full.

A client, however careful, does not restore Proton's threat model — a general-purpose IMAP or Gmail mailbox and zero-access encryption cannot both be true at once. If encrypted-at-rest storage is your team's hard requirement, Mailbox.org with PGP is the closer trade, and AI Emaily can still run against it. That is the whole placement.

How to choose for your team#

The chooser below is deliberately short. Most teams do not need eight rows of scoring; they need to know which one row is theirs.

1. 1

   You want the best team-mail workflow among the private providers

   Fastmail Teams. Shared mailboxes, delegation and admin are all first-class, native IMAP means any client works, and there is no seat minimum. Accept that it is not encrypted-at-rest the way Proton advertises — that is the trade that makes the team features actually work.

2. 2

   You picked Proton for the zero-access encryption and cannot lose it

   Mailbox.org with the PGP layer, or run a paid Proton Business for internal mail and route your team-facing shared inboxes (support@, sales@) through Mailbox.org or Fastmail. Neither hybrid is elegant, but it is the honest workaround for a real conflict between two features that cannot both be true at once.

3. 3

   You want the deepest team-mail features on a private-ish base for the least money

   Zoho Mail. Shared inboxes with agent assignment, delegated access, deep admin, EU data residency on request, and the lowest sustainable price on the page. The privacy story is thinner than the European providers; if that is disqualifying, this row is not yours.

4. 4

   Your team is already on Google Workspace or Microsoft 365 for everything else

   Stay on Workspace or Microsoft 365 for mail. Neither is private in Proton's sense, and switching mail providers alone while keeping Workspace or Microsoft 365 underneath for identity, calendar, drive and video is almost certainly moving cost around rather than solving anything. Layer a privacy-respecting client on top instead.

5. 5

   You want one Swiss-hosted, open-source suite for the whole team

   Kolab Now. Mail is one component; calendar, contacts, files and chat are the rest of the reason to pick it, and per-user roles across all of it are handled in one admin surface. IMAP plus Cyrus JMAP means any client still connects.

6. 6

   You want European privacy-first mail with built-in PGP for a small team

   Mailfence. Belgian jurisdiction, built-in OpenPGP in the web client, group accounts with shared calendar and contacts. Delegation is thinner than the top three rows, so this is right for small teams whose day is not driven by a shared support@ inbox.

What migration off Proton actually looks like for a team#

The mechanical part is the same as an individual migration, multiplied. Every provider on this page supports IMAP for mail import, so migrating means running an IMAP-to-IMAP transfer of each user's mailbox from Proton (through Bridge, one last time, on a machine per user or a batch server) to the new provider. Folders, dates and read state generally carry across; Proton labels do not always survive because IMAP folders are hierarchical and Proton labels are not exactly folders.

The parts most teams underestimate are three: domain cutover, shared-mailbox recreation, and calendar and contact migration. Point the MX records at the new provider only after every user's mailbox has finished importing, or new mail lands on the old provider while the import is still running. Shared mailboxes must be rebuilt on the new provider by hand — there is no protocol-level way to move a shared identity because Proton did not have one. Calendars and contacts migrate through CalDAV and CardDAV, which every provider on this page supports, but each account moves separately.

Once the mailboxes land, the last step is the client. If your team is staying on Apple Mail or Outlook, connection is a standard IMAP account per user. If you are adding an AI-native client on top, connect it to the new provider once per user and let it index; the client-layer setup is per-user, not per-provider.